Gravity Filters

Designed to soften produced water, by using an appropriate ion exchange medi

Softener Filters:

-  Blending of feed water and treated water to obtain the lowest cost operation.

-  Fully Automated control panels using PLC logic to control the operation of the NRU.

-  Counter current regeneration to best utilize salt and regeneration water with the addition of packed bed or resin hold down methods to reduce waste water volume.

Nitrate Ion Exchanger Filter:

This unit is used to remove nitrates from drinking water supplies in areas that experience nitrate leaching in well waters.  An anion exchange resin is used and regenerated with brine to reduce the nitrates in exchange for chlorides on the  resin.

Model details:

 These five 13' diameter upflow gravity filters each
produce 800 gpm from the Savannah River.  The
effluent water is consistently <1 NTU and < 5APHA
color units and is used for total plant process water.

The capacity of the upflow filter system ranges from 60 to 1,000 gpm. Multiple units can be coupled to accommodate any larger flow requirements.  By forcing the collected solids deep into the media, the upflow media filter achieves greater operational cycle time. Filter media types can vary or even be combined for maximum efficiency in a given application.  Options include silica sand, garnet and anthracite coal.  It is available in vertical open top or pressure vessels.

Contaminant particles are removed via an adsorbtion mechanism, rather than mechanical straining, resulting in the ability to remove submicron particles.  It is ideal for dirty river and lake feed water process streams, boiler feed pre-treatment, injection water, chlor-alkali plants, colloidal silica removal, SDI reduction, color removal, iron removal, and ion exchange & membrane system protection.  It is also used for removal of hardness precipitation in brine service.

 This graph demonstrates the effectiveness of the upflow filter in removing total suspended solids.  Curves marked "A" show influent and effluent levels on a 760 gpm system.  Note that the effluent levels did not exceed 0.45 mg/l , while the influent varies from 25 to 100 mg/l.  Curves marked "B" show a similar effectiveness in removal of suspended solids in a 1,200 gpm system.  Effluent quality remained below 0.4 mg/l, while the influent quality varied from 13 to 32 mg/l.

Key benefits over conventional clarification/sand filtration include:  installed cost is less, total automation and minimum levels of chemical addition (1-4 ppm) keep operating costs low, requires 75% less space, demineralizer resin life is lengthened due to a process stream virtually free of suspended solids and metal sulfates such as alum.  Removal of colloidal silica to levels of <0.1 mg/l eliminates cost of cleaning silica from turbine blades.

 Main Components of the Upflow Gravity Filter

CESCO offers a few different kinds of gravity filters.

Upflow Filter:

The upflow media filter offers high bed loading for solids removal and fine removal of solids and colloidal silica.  This design is used extensively on river water for pretreatment for cooling water or boiler makeup water.  It can remove 3 times the solids of conventional downflow media filters.  It operates at 6 gpm/sq ft for most applications.  It is used as a standard in the brine industry.